The flue curing of tobacco has evolved through several stages as far as the development of techniques is concerned. Initially, of course, curing was done in the conventional "tobacco barns" in which tobacco was strung on tobacco sticks, hung across rafters in the barn, and a fire was kept burning in the lower area of the barn with the heat rising through the tobacco and escaping through a roof opening. Improvements were made to this process to the extent that sheds were manufactured which included a gas or oil furnace which heated incoming fresh air and circulated it around and through the tobacco, with a portion of the heated air being recirculated, and a portion of it being drawn off as it became saturated with moisture from the tobacco (tobacco containing about 80.degree. water when it is placed in the barns). There have been several such attempts in the "bulk curing" of tobacco to use furnaces which provide heated air which is circulated and recirculated through the tobacco, however, none of these attempts have made very effecutal use of the heat, and of economic thermodynamic principles. For example, the barns are conventionally placed on a concrete slab which is directly in contact with the ground. As a result, the heated air which is usually introduced in the area directly beneath the tobacco first comes into contact with the concrete slab, and a considerable amount of heat is thus lost, necessitating the generation of additional heat than would otherwise be necessary. Additionally, the moist heat that is thrown overboard to make way for incoming amounts of drier heat is done so without any reclamation whatsoever of the heat therein. Even through some of the moist air effectively must be exhausted, the heat that is contained therein is very useful if it can be transferred to the incoming heat. No attempts at such heat reclamation have been made in the prior art to the best of applicant's knowledge.